Molecular Reconstruction for the High-Performance Recycled Fluororubbers.

Abstract

To address the challenges associated with the difficult recycling of fluorinated specialty materials and the subpar performance of recycled products, a molecular reconstruction strategy of oxidative degradation, fluorination addition is reported, and end-group transformation, which upcycled waste fluororubber into high-performance, chemically awakenable amino-terminated low-molecular-weight fluoropolymer (ATLF-Boc). Leveraging the chemical properties of the vinylidene fluoride structure in the waste fluororubber, carboxyl-terminated low-molecular-weight fluoropolymer (CTLF) with controlled molecular weight and end-group content are synthesized. Further, the whole chain is structurally strengthened at the molecular scale to achieve higher fluorine content and thermal stability, and saturated carboxyl-terminated low-molecular-weight fluoropolymer (SCTLF) is synthesized. Subsequently, to balance high reactivity and stable storage, high-performance ATLF-Boc is synthesized, realizing the upcycling of waste fluororubber. After upcycling, the awakened ATLF exhibits a high fluorine content (66.95%), and the cured ATLF shows the regulation of surface hydrophilicity and hydrophobicity (between 43° and 114°), a high tensile strength of 13.3 MPa, an excellent thermal stability (T_10% = 359 °C). In this study, a novel solution for the upcycling of waste fluororubbers for fabricating functional materials is offered, which is of great significance in the field of fluorinated specialty materials.